Agricultural equipment, such as a tractor or a self-propelled combine-harvester, includes an electro-hydraulic steering control system to adjust the position of one or more of a vehicle's wheels to adjust a moving direction of the vehicle. Steering control systems include electro-hydraulic valves which respond to a steering control signal generated by a steering device, such as a steering wheel or joystick, or a steering control signal provided by a global positioning system (GPS) signal. Steering control systems often include one or more sensors configured to sense a position of the steering device or a position of the wheels with respect to a frame of the vehicle. In these types of systems, a failure of an electro-hydraulic valve or an incorrect steering signal to an electro-hydraulic valve by the controller software can initiate an unwanted or undesirable steering action. Such a steering action is identified by one or more of the system sensors and interpreted by a system controller. Once the undesirable steering action is identified by the system controller, a corrective signal is generated by the system controller to prevent unintended steering resulting from the failure. The identification and response to the failure takes a certain amount of time, which is often too long to prevent an undesirable result. What is needed therefore is a steering control system, which is configured such that steering action cannot be initiated by an electro-hydraulic valve or electronic command only, but must also require steering initiation action by the vehicle's driver.